1. Field
Embodiments relate to a hinge assembly and an image forming apparatus having the same, and more particularly to a hinge assembly that hinge-connects a main body of an image forming apparatus and a cover unit to each other and an image forming apparatus having the same.
2. Description of the Related Art
An image forming apparatus is an apparatus which performs a document scanning function, such as a copy machine, a scanner, or a multifunction peripheral (MFP), and includes a main body having a scan transparent plate on which a document to be scanned is put and a cover unit that can hide the scan transparent plate.
Typically, the cover unit is pivotally connected to the main body through at least one hinge assembly. As a type of hinge assembly for connecting the cover unit and the main body to each other, a hinge assembly, which applies a variable elastic pressing force to the cover unit in accordance with an opening angle of the cover unit so that the cover unit can have a pre-stop function, may be used.
In such a hinge assembly, a coil spring is generally mounted as an elastic member that provides the elastic pressing force. It is ideal that the spring constant of such a coil spring is kept uniform. However, if the coil spring is used for a long time, the spring constant of the coil spring becomes relatively smaller than the spring constant when the coil spring is first manufactured due to plastic deformation of the coil spring.
There is a problem that, if the spring constant of the coil spring becomes smaller due to the long-term use of the coil spring, it is difficult to achieve smooth pre-stop of the cover unit. Further, due to impact that is applied to the main body as the cover unit is abruptly closed at high speed and collided with an upper side of the main body, the scan transparent plate and the cover unit may be damaged.
In order to prevent the above-described problem, there is a method to replace the hinge assembly with new one on a regular basis, but, it costs a lot to repair and replace the hinge assembly.